Clamping screw



' April 14, 1936. D, H HA ON 2,037,649

CLAMPING SCREW Filed Nov. 24, 1934 mm Daniel H Uhason mumm I Patented Apr. 14, 1936 UNITED STATES PATENT OFFICE CLAMIING SCREW Application November 24, 1934:,"v Serial No. 754,593

8 Claims.

This invention relates to clamping screws for holding various machine parts together, at least oneof the parts presenting a screw-engaging surface which. is other than flat, such as, the semi- 5 cylindrical lower end of a sewing machine presser-bar to which the vpresser-foot is customarily attached.

The present invention has for its object the provision of a clamping screw which may be read- 10 ily applied and tightened without special attention of the operator, and which will seat itself over an extended area of a semi-cylindrical or other non-flat surface.

With the above and other objects in View, as

15 will hereinafter appear, the invention comprises the devices, combinations, and arrangements of parts hereinafter set forth and illustrated in the accompanying drawing of a preferred embodiment of the invention, from which the several features of theinvention and the advantages attained thereby will be readily understood by those skilled in the art.

The several features of the present invention will be clearly understood from the following de- 25 scription and accompanying drawing in which:

Figure 1 is a front elevation showing my improved screw used to secure an attachment to the lower end of a sewing machine presser-bar having a semi-cylindrical cross-section.

30 Figure 2 is a side elevation, partly in section, showing my improved clamping screw in its initially inserted position.

Figure 3 is a View taken substantially along the line 33 of Figure 1.

35 Figure 4 is a top plan view of my improved clamping screw and Figure 5 is a disasssembled perspective view.

As illustrated in the drawing, 1 represents the lower end of the hollow head of a sewing ma- 40 chine in which is journaled for endwise movement the usual presser-bar 8 having a rounded or semi-cylindrical shaped lower portion 9 provided with the usual threaded aperture 9'.

A pinking attachment I0 having a boss II is 45 provided with an internally threaded aperture l2 which receives the threaded end l3 of the knurled-headed thumb-screw l4. Made integral with the knurled head is a reduced portion l5 forming a shoulder and at the junction of the 50 shoulder and head there is provided a circumferential 'groove l6. Slidably and rotatably mounted on the shank Id of the screw is a sleeve I! having a concaved end l8 which engages the semi-cylindrical lower portion 9 of the presser- 55 bar. The other end of the sleeve is formed with a reduced shouldered portion [9 which is provided with a circumferential groove 20.

A helically wound compression-spring 2| has one of its ends fitted into the groove 20 in the shouldered portion IQ of the sleeve 11 and 5 its other end fixed in the groove [6 in the shoulderedportion I5 of the screw.

When used, the screw is first passed through the usual aperture in the presser-bar and inserted in the threaded boss I I of the pinking attachment; In this position the concaved end 3 of the sleeve engages the rounded portion 9 of the presser-bar and assumes its correct position and is held in this position by the compression-spring 2| while the screw is being tightened to a point 15 in which the shoulder. l5 engages the shoulder 19 of the sleeve IT to rigidly secure the pinking attachment ill to the presser-bar.

From the above it will be obvious that the sleeve I! is rotatably attached: to the screw I4 20 by the compression-spring 2| which prevents the sleeve from being misplaced when the screw is removed and permits the sleeve to assume its correct position without special attention.

From the foregoing description considered in connection with the accompanying drawing, the construction, manner of operation and several advantages of my improved clamping screw will be clearly and fully understood. It is apparent that such a device has a wide variety of uses, and 80 it will be fully understood that the form, construction and arrangement of the several elements employed may be varied. For instance, the clamping face I8 of the sleeve may be convex or it may have a portion of its clamping face inclined to aplane normal to the axis of the shank in order to make it complemental to the surface it is intended to engage. Therefore, the privilege is reserved of resorting to all such legitimate changes therein as may be fairly embodied within the spirit and scope of the appended claims.

Having thus set forth the nature of the invention, what I claim herein is:-

1. A screw having a head with a shoulder formed integral therewith and a threaded shank, a peripherally shouldered sleeve slidably and freely embracing said shank and formed with a recess in the shoulder thereof and a spring embracing said shank with one of its ends secured to said shoulder and its other end rotatably anchored in the recess in said shouldered sleeve.

2. A screw having a head and a threaded shank formed with a shoulder, a sleeve slidably embracing said shank, said sleeve having at least a portion of its clamping end face inclined to a plane normal to the axis of said screw and its other end formed with a shoulder, and a helical spring surrounding said shank and embracing said shoulders for rotatably and yieldingly securing said sleeve to said screw.

3. A screw having a head and a threaded shank formed with a circumferentially grooved shoulder, a sleeve slidably embracing said shank and having one of its ends formed with a circumferentially grooved shoulder and its other end having at least a portion of its clamping face inclined to a plane normal to the axis of said shank and a helically wound spring surrounding said shank and shoulders and having its ends anchored in said grooves for rotatably and resilient- 1y securing said sleeve to said shank.

4. A clamping device for securing an attachment to the cylindrical lower portion of the presser-bar of a sewing machine comprising a screw having a head and a threaded shank formed with a shoulder, a sleeve slidably embracing said shank and having its clamping face formed complemental to the semi-cylindrical lower portion of the presser-bar, and a helically wound spring surrounding said shank, said spring having one of its ends secured to said sleeve and its other end rotatably secured to said shank.

5. A clamping device for securing an attachment to the rounded lower portion of the presser-bar of a sewing machine, comprising a screw having a head and a threaded shank formed with a shoulder, a sleeve slidably embracing said shank and having one of its ends formed with a circular shoulder and its other end formed complemental to the rounded lower portion of the presser-bar, and means for slidably and yieldingly securing said sleeve to said screw, said means permitting the shoulder on said screw to engage the shoulder on said sleeve when the screw is tightened.

6. A screw having a head and a shoulder adjacent said head, said screw having a threaded shank, a non-threaded sleeve freely slidable endwise of and upon said shank in position to be engaged by said shoulder, and a coil-spring yieldingly urging said sleeve away from said shoulder, said spring being connected at one end to said sleeve and at its other end to said screw to prevent endwise separation of said sleeve and screw.

7. A screw having a head and a shoulder adjacent said head, said screw having a threaded shank, a non-threaded sleeve freely slidable endwise of and upon said shank in position to be engaged by said shoulder, and a coil-spring yieldingly urging said sleeve away from said shoulder, said spring being connected at one end to said sleeve and at its other end to said screw to prevent endwise separation of said sleeve and screw, the connection at at least one end of said spring being a circularly recessed connection permitting relative rotation between the spring and the part connected thereto.

8. A screw having a head and a shoulder adjacent said head, said screw having a threaded shank, a non-threaded sleeve freely slidable endwise of and upon said shank in position to be engaged by said shoulder, said sleeve having a clamping face at least a portion of which is inclined to a plane normal to the axis of said screw, and a coil-spring yieldingly urging said sleeve away from said shoulder, said spring being connected at one end to said sleeve and at its other end to said screw to prevent endwise separation of said sleeve and screw, the connection at at least one end of said spring being a circularly recessed connection permitting relative rotation between the spring and the part connected thereto.

DANIEL I-I. CHASON. 

